diff --git a/README.md b/README.md
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--- a/README.md
+++ b/README.md
@@ -182,9 +182,9 @@ In addition to their math elective, students must complete the following course
 
 Courses | Duration | Effort | Notes | Prerequisites | Discussion
 :-- | :--: | :--: | :--: | :--: | :--:
-[Calculus 1A: Differentiation](https://www.edx.org/course/calculus-1a-differentiation) | 13 weeks | 6-10 hours/week | [high school math](FAQ.md#how-can-i-review-the-math-prerequisites) | [chat](https://discord.gg/mPCt45F)
-[Calculus 1B: Integration](https://www.edx.org/course/calculus-1b-integration) | 13 weeks | 5-10 hours/week | Calculus 1A | [chat](https://discord.gg/sddAsZg)
-[Calculus 1C: Coordinate Systems & Infinite Series](https://www.edx.org/course/calculus-1c-coordinate-systems-infinite-series) | 6 weeks | 5-10 hours/week | Calculus 1B | [chat](https://discord.gg/FNEcNNq)
+[Calculus 1A: Differentiation](https://openlearninglibrary.mit.edu/courses/course-v1:MITx+18.01.1x+2T2019/about) ([alt](https://ocw.mit.edu/courses/mathematics/18-01sc-single-variable-calculus-fall-2010/index.htm)) | 13 weeks | 6-10 hours/week | The alternate covers this and the following 2 courses | [high school math](FAQ.md#how-can-i-review-the-math-prerequisites) | [chat](https://discord.gg/mPCt45F)
+[Calculus 1B: Integration](https://openlearninglibrary.mit.edu/courses/course-v1:MITx+18.01.2x+3T2019/about) | 13 weeks | 5-10 hours/week | - | Calculus 1A | [chat](https://discord.gg/sddAsZg)
+[Calculus 1C: Coordinate Systems & Infinite Series](https://openlearninglibrary.mit.edu/courses/course-v1:MITx+18.01.3x+1T2020/about) | 6 weeks | 5-10 hours/week | - | Calculus 1B | [chat](https://discord.gg/FNEcNNq)
 [Mathematics for Computer Science](https://openlearninglibrary.mit.edu/courses/course-v1:OCW+6.042J+2T2019/about) ([alt](https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-042j-mathematics-for-computer-science-spring-2015/index.htm)) | 13 weeks | 5 hours/week | An alternate version with solutions to the problem sets is [here](https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-042j-mathematics-for-computer-science-fall-2005/assignments/). Students struggling can consider the [Discrete Mathematics Specialization](https://www.coursera.org/specializations/discrete-mathematics) first. It is more interactive but less comprehensive, and costs money to unlock full interactivity. | Calculus 1C | [chat](https://discord.gg/EuTzNbF)